Heat the milk with the cinnamon stick and lemon peel. Do not let it boil. Let it sit to infuse.

In a bowl, combine the sugar, flours, and egg yolks. Whisk until smooth. If the mixture is too thick, add a little milk.

Return the milk to the heat, and when it starts to boil, add the other ingredients. Whisk quickly to prevent lumps. It will thicken fast.

Transfer the cream to a container and cover with plastic wrap to prevent a skin from forming. Set aside.

Preheat the oven to 350°F (180°C).

Weigh and sift the flour. Weigh the sugar.

Line a baking sheet with parchment paper and brush with butter.

Separate the egg yolks from the whites and beat the whites until stiff peaks form.

Add the sugar and continue beating.

Gently fold in the flour and baking powder, moving from bottom to top.

Spread the batter evenly on the baking sheet and bake for about 15 minutes, depending on your oven. Check with a toothpick; if it comes out clean, it's done.

Remove the parchment paper, spread the pastry cream over the cake, and roll it up. It's ready to serve.

You can dust the top with powdered sugar or cocoa. Enjoy!